1. Technical Field
The present invention relates to location estimation systems and, more specifically, to location estimation systems that incorporate triangulation techniques to determine a location.
2. Related Art
Location estimation devices exist for all types of sports, navigation, and asset tracking systems. Golf, for example, is well known for having many location estimation devices that utilize GPS and/or telescoping systems in a sometimes-futile attempt to help the golfer place the ball close to the pin. GPS systems are also used for automotive and other outdoor navigational systems. Initially, GPS was developed for military applications. Casual users, such as sailors, were required to use other less accurate technologies such as the sextant or, more recently, Loran to navigate their way across a body of water. Eventually, GPS technology was made accessible to the public but with a reduced accuracy. Recently, however, GPS systems have been allowed to be made public that have sufficiently higher levels of accuracy. The accuracy of a GPS system may be within a few meters of the indicated location. As such, GPS receivers are now common in navigation systems, cell phones, and even watches.
One problem with GPS receivers, however, is that GPS signals that allow the receiver to triangulate the receiver's location often do not reach receivers that are within a structure. As such, other technologies such as accelerometers and magnetometers are used to supplement GPS data to generate estimates of the location in place of the GPS data. Such systems, however, very rapidly become highly inaccurate thereby effectively terminating location estimation functionality after even a short period of time. Generally, a need exists for a location estimation system that maintains positional accuracy even within structures such as office buildings, warehouses and hospitals.